I agree that plaster actually mixed with clay would probably be a disaster. I've always been told the same thing -- if the wedging board is chipping and bits of plaster get in your clay, it's bad news.
When I heated plaster it was only to use the pieces as molds to in which to melt glass.
GeorgiaMark Alexander <firstname.lastname@example.org> wrote:
>I had always been told that plaster in the kiln spells disaster. I had always assumed it would just burn up but when in contact with clay it would cause problems with unequal expansion and contraction rates. I had always been warned that wedging boards and molds had to be very carefully monitored and even plaster and clay modeling tools had to be kept strictly seperate to prevent the infiltration of plaster in the firing clay. Of course at one time tomatoes were considered poisonous and no one combined peanut butter and jelly, so who knows? Why does your co-worker want to do this?
> email@example.com wrote:A question for my friends... The other art teacher at school wants to fire plaster in the kiln. If this is safe and how must it be done? Are there any special instructions that we need to know before she tries it? Thanks for your replies, Idus in Southern Mississippi ( about one hour from New Orleans)---
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